People with severe and persistent mental illness (SMI) such as schizophrenia, bipolar disorder, or major depressive disorder are at disproportionally high risk for poor education, inadequate housing, and social supports. Despite the availability of effective treatments that promote recovery, many people with SMI do not access services except in costly urgent care settings, e.g., hospitals, jails, and prisons.1-4 Treatment via urgent care in lieu of other preventive care strategies increases the risk of relapse, suicidality, and poorer overall functioning.5 Employment activity may decrease hospital service use by providing structure and stability, enhancing social support, helping people escape from poverty, improving motivation, and decreasing symptoms.6, 7 The proposed dissertation will employ data from a randomized controlled trial of supported employment, medication management, and other behavioral health services versus usual care. These data contain 2,238 working age individuals with schizophrenia or mood disorder enrolled in Social Security Disability Insurance from 23 cities, receiving enhanced or usual mental healthcare and health insurance. This R36 grant proposal aims to use longitudinal multilevel modeling: (1) to determine the size and causal direction of associations between work and hospital care use; and (2) to test whether the relationship between work and hospital service use is sensitive to job intensity, job stability, or job fit.!A large body of evidence consistently demonstrates that peopl with severe and persistent mental illness can and do participate in the competitive workforce when provided appropriate supports.8 Thus, this study will provide information on the effectiveness of a feasible strategy to reduce costly and inefficient healthcare utilization.